1. Field of the Invention
This invention relates to a bicycle wheel, more particularly to a retaining device adapted to retain tensely spokes between a wheel rim and a hub of the bicycle wheel.
2. Description of the Related Art
A conventional bicycle wheel includes an axle with two axle ends to be carried by two prongs of a bicycle fork, a wheel rim, a hub rotatably mounted on the axle between the axle ends, and a plurality of spokes connecting the hub to the wheel rim. Each spoke is connected to a respective engaging groove in the hub by a spoke tightening member. The tightening member includes a stem portion in which the spoke is secured threadedly, and an enlarged head portion which abuts against an annular inner wall of the hub so as to tighten tensely the spoke between the wheel rim and the hub. However, the spoke tightening member tends to be loosened to move toward the axle after a long term use and thus loosens the spoke, thereby resulting in uneven tension among the spokes and deforming of the wheel rim.
The object of the present invention is to provide a retaining device which guards spoke tightening members that engages a tubular mount member of a hub against movement toward an axle so as to ensure tension of spokes between a wheel rim and the hub.
According to this invention, the retaining device includes a pair of annular retaining members and a pair of securing members. Each annular retaining member is adapted to be interposed between an axle and enlarged head portions of spoke tightening members in an annular space defined between the axle and an annular inner peripheral wall of a tubular mount member. The annular retaining member includes an annular inner ring portion which is adapted to be sleeved on the axle from an axle end to the tubular mount member, an annular outer ring portion which surrounds and which is rotatable relative to the annular inner ring portion, and a rolling element which is disposed between the annular inner and outer ring portions. Each securing member is disposed to secure the annular inner ring portion on the axle such that the annular outer ring portion is adapted to face towards the enlarged head portions of the spoke tightening members so as to guard shoulders of the spoke tightening members against being loosened from abutment with the inner peripheral wall.